The present invention generally relates to erosion control matting, and more specifically relates to temporary or permanent turf reinforcement and soil retention matting.
Erosion control is an essential environmental consideration when new slope embankments and channels are created, for example during construction of buildings and drainage systems. Traditionally, newly constructed channels have been lined with concrete or rock to provide a hard, armor-like channel lining. Alternatively, the development of root reinforcement systems are relied upon to control erosion. Thus, methods have been developed for stabilizing soil on channel linings and other erosion prone surfaces by encouraging the growth of native or introduced vegetation along the surface. Ideally, a mature root system within the sloped surface functions to bond together the channel surface and inhibit soil loss during rains and other stresses.
However, embankment and channel surfaces often require reinforcement, particularly during the pre-vegetated stage and early stages of plant growth, to prevent loss of soil, seeds, seedlings and other small plants when the soil is in an unstable state.
Various reinforcement systems have been developed. For example, U.S. Pat. No. 5,849,645 to Lancaster, which is incorporated herein by this specific reference, discloses a reinforced composite matting including a fiber matrix secured together by an arrangement of multiple nettings. The nettings form a series of alternating troughs and ridges, from between one eight an inch in height to one inch in height, along the matting. This three dimensional, “cuspated” aspect of the Lancaster matting is designed to trap mulch, sediment, and plant seeds in the troughs during early stages of plant growth. According to Lancaster, the trapped soil and other debris provides a growing medium for sprouting plants. Although the Lancaster patent recognizes the problems associated with erosion on new channel surfaces, the matting system disclosed does not address other problems, for example, high shear stress on the matting, particularly during long duration, high velocity water flow during the critical pre-vegetated stage. Furthermore, the Lancaster system requires that the matting be placed in a specific alignment with respect to channel flow. More particularly, Lancaster discloses that in order for the matting to trap sediment between the troughs and ridges, the matting is to be installed such that the troughs and ridges are perpendicular to the intended direction of channel flow. This requirement poses potential installation problems and setbacks.
Conventional prior art erosion control blankets have utilized wheat straw, coconut fiber, chopped or crimped synthetic polypropylene fibers or a blend thereof. Wheat straw, in particular, has long been an industry standard. Erosion control blankets made primarily of wheat straw suffer a number of disadvantages. For example, the natural decomposition process of wheat straw tends to extract nitrogen and other plant nutrients from the soil surface to which the straw is applied, thus detrimentally affecting soil fertility. Plants and seedlings growing from the surface and through the wheat straw-based covering does not promote the optimal growth of plant roots, thus delaying or hindering the goal of soil stability. To counteract this effect, fertilizers and other such additives are oftentimes incorporated into the blanket material in an effort to maintain or boost soil fertility during the early stages of plant growth.
It will be appreciated by those of skill in the art, that the objectives of the present invention, for example, greater soil stability and establishment of foliage and a healthy root system, are essentially the same objectives to which conventional erosion control blankets have generally been directed. However, conventional erosion control blanket designs have been inadequate, particularly during high velocity, long term, sustained water flow conditions, and even more so when said blankets have been installed to a non-vegetated, bare or seeded soil surface.
There is still a need for a better erosion control product. The present invention provides a more effective, more technically advanced system for controlling soil loss erosion on channel and embankment surfaces, particularly during the critical pre-vegetation stage and in areas exposed to severe conditions of continuous, extended, high velocity water flows, and high shear stress erosion.